We had that problem in the Navy with a lot of our gear, we figured it was caused by Minahoonies. But as soon as we gave up and ignored it they went away and no more squeaks. Apparently Minahoonies don't like to be ignored and they go away. I guess they have left the Navy equipment and moved to the RVs. So I guess the remedy is to just ignore them and if they aren't too noisy eventually they will go away.
... Dave